arXiv subjects

Oscar Carrión-González

Publications and source records attributed to Oscar Carrión-González.

3 recordsLinked to original sources

arXiv2026

The Nancy Grace Roman Space Telescope Coronagraph Community Participation Program

In preparation for the operational phase of the Nancy Grace Roman Space Telescope, NASA has created the Coronagraph Community Participation Program (CPP) to prepare for and execute Coronagraph Instrument technology demonstration observations. The CPP is composed of 7 small, US-based teams, selected competitively via the Nancy Grace Roman Space Telescope Research and Support Participation Opportunity, members of the Roman Project Team, and international partner teams from ESA, JAXA, CNES, and the Max Planck Institute for Astronomy. The primary goals of the CPP are to prepare simulation tools, target databases, and data reduction software for the execution of the Coronagraph Instrument observation phase. Here, we present the current status of the CPP and its working groups, along with plans for future CPP activities up through Roman's launch. We also discuss plans to potentially enable future commissioning of currently-unsupported modes.

astro-ph.IM↗

arXiv2026

The Roman Coronagraph Community Participation Program: early calibration plan and pilot observation of a companion

Roman is set to launch in weeks! The Coronagraph Instrument - technology pathfinder for future direct imaging missions - is ready to fly too. According to predictions, laboratory tests and high fidelity simulations, it will open a new contrast regime enabling the imaging of mature, giant planets in visible reflected light. The Community Participation Program is responsible for preparing a comprehensive observing program with associated data processing software and calibrations. We give a brief update about the on-going "baseline" calibration plan for the first months. Additionally, we describe a pilot program aiming for the stellar companion HD 29992 B at moderate ~1e-5 to ~1e-6 Band 1 (575 nm) contrast, to be carried out as soon as the instrument is operational. The idea is to generate a canonical data set with a self luminous companion that is easily recoverable. This functional checkout will be precious to best prepare our community, exercise our calibration plan and suite of tools.

astro-ph.IM↗

arXiv2026

ngVLTI: Cost and Feasibility of a Four-Telescope VLTI Expansion for Milliarcsecond-Scale Imaging

We assess the cost and technical feasibility of extending the Very Large Telescope Interferometer (VLTI) through the addition of four 8 m-class Unit Telescopes (UTs), an upgrade we refer to as the new generation VLTI (ngVLTI). Such an upgrade would provide a dense and homogeneous uv coverage with baselines up to 220 m, enabling true imaging at milliarcsecond angular resolution across science cases ranging from Solar System bodies to distant active galactic nuclei. Because each image is reconstructed at a single wavelength, repeating the reconstruction across the spectral channels of the instrument would deliver spectral-imaging cubes -- a qualitatively new capability for the VLTI, bringing it close to the imaging power of ALMA at near-infrared wavelengths. Motivated by this scientific case, we examine a compact telescope concept consisting of a fast ($f/0.64$), segmented, parabolic primary mirror feeding a subterranean coudé focus compatible with the existing VLTI infrastructure. We summarise the optical design, which achieves diffraction-limited performance over a 1 arcmin field of view and a well-matched reimaged pupil, discuss the mechanical trade-offs behind the choice of a 60-segment, 1.2 m primary -- a mirror mass of ~13.5 tons and an altitude moving mass of ~50 tons -- and quantify the gravitational flexure of the telescope structure and its resulting optical sensitivity as a function of pointing elevation. We then present a back-of-the-envelope cost estimate of order 80 MEuro per telescope (2026 prices), broken down into the segmented primary, adaptive secondary, coudé train, mount, enclosure, and ancillary instrumentation. The proposed upgrade appears both cost-competitive and technically achievable, offering a long-term perspective for Paranal Observatory in the ELT era.

astro-ph.IM↗